(a) Notice Any party to an included action in a pending petition for coordination must promptly provide notice of any potential add-on cases in which that party is also named or in which that party’s attorney has appeared. The party must submit notice to the coordination motion judge and the Chair of the Judicial Council and serve it on each party appearing in the included actions in the pending petition and each party appearing in the potential add- on cases.
Rule 3.531.Potential add-on case
Division 4. Parties and Actions · Chapter 7. Coordination of Complex Actions · Article 3. Petitions and Proceedings for Coordination of Complex Actions · Adopted 2005 · no amendments on record · Last verified July 29, 2026
In one sentenceRule 3.531 requires a party to an included action in a pending coordination petition to promptly notify the coordination motion judge and the Chair of the Judicial Council of any related case the party is also named in, and lets that potential add-on case be treated as an included action by stipulation or order.
Full Text of Rule 3.531
(b) Stipulation or order By stipulation of all parties or order of the coordination motion judge, each potential add- on case will be deemed an included action for purposes of the hearing on the petition for coordination.
Plain-English Summary
A coordination petition rarely captures every related lawsuit on the day it is filed. Rule 3.531 addresses the ones that surface afterward — cases a party to an included action is also named in, or cases where that party’s own attorney has appeared, that could belong in the same coordination proceeding.
The party who knows about a case like that has to speak up. Rule 3.531(a) requires prompt notice to the coordination motion judge and the Chair of the Judicial Council, plus service on every party in the included actions already part of the petition and every party in the potential add-on case itself.
Notice alone does not fold the new case in. Under Rule 3.531(b), a potential add-on case counts as an included action for the coordination hearing only once all parties stipulate to it or the coordination motion judge orders it.
Frequently Asked Questions
What counts as a “potential add-on case” under this rule?
A case in which a party to an included action in the pending petition is also named, or in which that party’s attorney has appeared, that is related to the pending coordination petition.
Who has to give notice of a potential add-on case?
The party to the included action who is also named in, or whose attorney has appeared in, the related case.
Does notice automatically make the add-on case part of the coordination petition?
No. It becomes an included action for purposes of the hearing only by stipulation of all parties or by order of the coordination motion judge.
Who receives notice of a potential add-on case?
The coordination motion judge and the Chair of the Judicial Council, plus every party in the included actions and every party in the potential add-on case.
Amendment History
Rule 3.531 renumbered effective January 1, 2007; adopted as rule 1531 effective January 1, 2005.
Source & verification. Rule text is reproduced verbatim from
the Judicial Council of California. Adopted by the Judicial Council of California.
Last verified July 29, 2026.
· Official source
Also known as: add-on case coordination petition californiacrc 3.531 potential add-on noticerelated case not in original coordination petitionstipulation to include add-on case